Automatic pet doors actuated by a magnet worn by a pet have numerous advantages over other types of automatic pet doors. These advantages include preventing unauthorized pets from opening the pet door, allowing the authorized pets to open the pet door without having to force it open, being relatively secure against burglars, reliably weatherproof and inexpensive to provide and install.
However, automatic pet doors actuated by a magnet worn by a pet of the prior art have a disadvantage, namely, either they only work for small pets or they require a large and expensive electric motor to accommodate larger and heavier pet doors for large pets. Specifically, a pet door for a 100 to 200 lb dog would have to be about 36″×14″, or even larger and weigh about 10 lb. or more. Such a heavy pet door requires at least a 3 Amp electric motor to actuate. A 3 Amp electric motor is quite expensive and also large in size, therefore difficult to install inside a rather slender frame for the automatic pet door assembly.
Therefore, there is a need for an automatic pet door for large pets actuated by a magnet worn by a pet that does not require a large and expensive electric motor.